To supply an electric motor with current, it is conventional, with the aid of a half-bridge circuit, to convert the direct voltage available in an intermediate circuit into alternating current for the individual motor phases. To that end, for each motor phase, a half-bridge circuit is needed, with whose two semiconductor switch elements the motor phase is switched alternately to the positive or negative conductor bar of the intermediate circuit. In this context, usually the pulse-width modulation method (PWM method) is used, in which a PWM signal is conditioned such that the two semiconductor switch elements are able to be driven.
German Published Patent Application No. 10 2005 020 805 describes such a half-bridge circuit operated according to the PWM method, and explains that when switching between the two semiconductor switch elements, it is important to adhere to a locking time or block time during which both semiconductor switch elements are turned off and therefore are non-conductive, since otherwise there is a possibility of a short-circuit between the positive and negative conductor bar. German Published Patent Application No. 10 2005 020 805 also describes how such a block time is able to be produced. The delay of rising edges of the PWM signals ensures that a block time is observed. According to at least one arrangement, the falling edges of the PWM signals are also delayed, and specifically by an OFF delay (td1) which is smaller than the ON delay (te1+td1) of the rising edges. The block time is then the difference of the two delay times.